Definition - What does Psychrometer mean?

Psychrometer refers to a device for determining relative humidity in the atmosphere by the reading and comparing of two thermometers: the dry-bulb and wet-bulb air temperatures. The psychrometer is one kind of hygrometer.

A psychrometer has many uses both in the home and industry. Apart from measuring relative humidity and weather forecasting, it is also used for air conditioning maintenance and appropriate humidity levels for manufacturing. Meteorology departments rely on psychrometers to forecast weather and precipitations.

Corrosionpedia explains Psychrometer

A psychrometer is an instrument to measure the water vapor content or relative humidity of the air. It comprises two identical thermometers:

  • Wet-bulb thermometer – measures temperature by the bulb being dipped in liquid. Its bulb is covered with a jacket of tight-fitting muslin cloth that can be saturated with distilled water.
  • Dry-bulb thermometer – measures temperature by being exposed to the air.

It is easy to determine the relative humidity of the surrounding area by computing the difference between the two bulb temperatures in a psychrometer. Some precautions must be taken during the use of a psychrometer. Avoid heating the thermometer or placing it somewhere in extreme weather. This could give a misleading reading of temperatures.

Psychrometers come in two types:

  • Sling psychrometer – the thermometers are linked to a grip or span of rope and spun around in the air for some time. It is seldom used for field computations. It is now substituted by more suitable electronic sensors.
  • Whirling psychrometer – two thermometers are fixed up into an instrument that looks like a ratchet or football rattle.

Psychrometers are mostly used in meteorology, and in the heating, ventilation, and air conditioning industry for correct refrigerant charging in both residential and commercial areas. Psychrometers are fabricated from stainless steels, which are resistant to corrosion.

This definition was written in the context of relative humidity

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